iBeacon sends alerts to your home screen when you're standing near an Apple store or other hotspot.

If you own any iPhone more recent than the 4, walk into any US Apple retail store today and you’ll get a taste of the possibly-dystopian future of retail and the internet of things. That’s because
Apple just rolled out a technology called iBeacon in all 254 of its US stores
, and if you say “yes” to the prompts it will push to your phone when you walk in the front door, it will start sending alerts to your home screen with information and promotions when you’re standing next to pre-designated hotspots.

For example, if you walk by the table of shiny, new iPhones with your sad, old iPhone in hand, you may get a notification that it’s time to upgrade, along with the chance to check your eligibility for one.

iBeacon welcomes you to stores equipped with the technology. Apple

Here’s how it works: iBeacon allows iPhones to locate their position in space with centimeter precision. It does this by using the phone’s Bluetooth Low Energy radio to listen for the radio-frequency cries of various “beacons” that retailers must place throughout their store. With such a positioning system in place, store owners can designate certain areas in their shops—as small as tens of centimeters across—where actions can be triggered, like sending more information or a promotional offer to a customer’s phone.